The invention relates to an ultrasonic imaging apparatus operating according to the impulse-echo method, particularly intended for medical diagnostics, comprising an ultrasonic applicator for the linear ultrasonic scanning of an examination subject and an image display device with a line generator for the reproduction of the echo impulses as lines, as well as an image generator for the displacement of the line as a function of the displacement of the ultrasonic beam in the subject, whereby the ultrasonic scanning proceeds in partial images which are summated into the total image on the display device according to an interlaced scanning procedure.
An ultrasonic imaging apparatus of this type has already been proposed which operates with a total of three partial images which occur in succession and which are summated into the total image in an interlaced fashion according to an interlaced scanning procedure. The recording of each partial image on the display device (electron beam tube) proceeds with a deflection raster corresponding to that of the ultrasonic scanning in the examination subject for the respective partial image. There thus results on the image recording device a line sweep frequency for each partial image which amounts to only one-third of that particular sweep frequency which would have to be employed in the case of a total image recording procedure. Due to this strongly reduced line sweep frequency, particularly when the line density of each partial image is relatively low, the result can be the visual impression of a line raster running in a horizontal direction. Viewing of the image is consequently seriously disturbed.